Amobarbital

What it isAn intermediate-acting barbiturate that positively modulates the GABA-A receptor, prolonging chloride channel opening.

Why this oneIts historical niche is the "Amytal interview" and, in neurology, the intracarotid Wada test for hemispheric language and memory lateralization.

What limits itBarbiturates have no ceiling on respiratory depression, a narrow therapeutic index, high dependence liability and strong CYP induction — which is why benzodiazepines displaced them.